J.P. Morgan reported that its markets revenue–which includes revenue from its fixed-income arm as well as from equities trading — fell 14% to $4.65 billion in the second quarter from a year earlier. Goldman Sachs said net revenues in its fixed income, currency and commodities unit slid 10% compared to the second quarter of 2013, while its equities division experienced a 13% fall in net revenues.

Bank executives began sounding alarm bells about the trading slowdown in late May. Citigroup 's chief financial officer John Gerspach warned the bank’s trading revenue could drop by 20% to 25% overall, while J.P. Morgan said it expected its markets revenue to drop 20% in the second quarter.

The indication so far is that it could be short-lived. On a conference call Tuesday morning, J.P. Morgan CFO Marianne Lake said that while June saw higher levels of activity, “that has not carried on into July yet.”

“We are going to run the business being prepared for lower activity,” said J.P. Morgan CEO Jamie Dimon.